RFIC device and method of fabricating same

ABSTRACT

A radio frequency integrated circuit (RFIC) device and methods for fabricating same are disclosed. The RFIC device includes: a first semiconductor layer having a first surface, a second surface parallel to the first surface and a thickness of smaller than 3 μm; a first dielectric layer on the first surface of the first semiconductor layer; a semiconductor component within the first semiconductor layer and the first dielectric layer; a second dielectric layer on the second surface of the first semiconductor layer, the second dielectric layer having a thickness of smaller than 1 μm; and a sheet-like heat sink formed on a surface of the first dielectric layer opposite to the first semiconductor layer for dissipating heat from the semiconductor component. Efficient dissipation of heat from an RF transistor to a certain extent can be achieved by the RFIC device.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the priority of Chinese patent applicationnumber 201710322564.0, filed on May 9, 2017, the entire contents ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to the field of semiconductor technologyand, in particular, to a radio frequency integrated circuit (RFIC)device and methods of fabricating the device.

BACKGROUND

Silicon-on-insulator (SOI) substrates have overwhelming advantages overbulk silicon. It provides IC components formed thereon with gooddielectric isolation which immunizes them from parasitic latching thatcomplementary metal oxide semiconductor (CMOS) circuits formed on bulksilicon suffer from. In addition, ICs fabricated on SOI substrates offerthe advantages including small parasitic capacitance, a high integrationdensity, a high operating speed, simple fabrication processes, smallshort channel effects and high suitability for use as low-voltagelow-power consumption circuits. Thanks to their inherent advantage ofhigh insulation, CMOS devices on SOI substrates are ideal for use as keycomponents and circuits at RF front-ends, including RF switches, low SNRpower amplifiers, modulators and their circuits.

Compared to those on bulk silicon substrates, CMOS RF switches on SOIsubstrates are remarkably superior in terms of insertion loss andisolation. However, as many CMOS RF components formed on the top siliconthin-film such as RF CMOS switches and CMOS low noise amplifiers (LNAs)are still in electrical coupling with the silicon substrate underlyingthe insulating layer, during the operation of such components, inparticular RF CMOS switches, additional variable parasitic capacitancewill occurs which can dramatically affect the linearity of a passedsignal. Additionally, a rather large part of the passed signal will beconsumed in the silicon substrate due to the coupling.

Theoretically, an ultimate measure to eliminate such coupling betweenthe RF CMOS devices on the top silicon thin-film and the siliconsubstrate is to remove the silicon substrate during the fabrication ofthe RF CMOS switches, which, however, may lead to a number of adverseconsequences, in particular, lower heat dissipation capabilities of theRF CMOS switches. As a result, upon the application of high signal powerin a short period of time, overheating may occur and the reliability ofthe components may be impaired.

SUMMARY OF THE INVENTION

It is an objective of the present invention to propose a novel RF switchand IC device and methods of fabricating them to overcome theoverheating-caused low reliability problem.

In one aspect of the present invention, there is provided a novel radiofrequency integrated circuit (RFIC) device including:

a first semiconductor layer having a first surface, a second surface anda thickness of smaller than 3 μm;

a first dielectric layer on the first surface of the first semiconductorlayer;

a semiconductor component within the first semiconductor layer and thefirst dielectric layer;

a second dielectric layer on the second surface of the firstsemiconductor layer, the second dielectric layer having a thickness ofsmaller than 1 μm; and

a sheet-like heat sink that is formed on a surface of the seconddielectric layer opposite to the first semiconductor layer fordissipating heat from the semiconductor component.

First of all, it is worthy to mention that the semiconductor componentincludes at least one first transistor and that the first semiconductorlayer has a thickness of smaller than 3 μm while the second dielectriclayer has a thickness of smaller than 1 μm. It is stressed here that thefirst semiconductor layer for the formation of crucial active componentsof the RFIC device represented by the first transistor has a thicknessof smaller than 3 μm (or even 0.2 μm particularly when the RFIC deviceis to be deployed in an RF front-end) and vertically isolated by thefirst and second dielectric layers at its upper and lower sides becausethis, on the one hand, is intended to reduce or even prevent, in thevertical direction, external electrical or electromagnetic interferenceby virtue of the two dielectric layers, and on the other hand, canminimize parasitic effects for transistors formed on the semiconductorlayer.

In addition, construction of an efficient heat-dissipating componentexternal to the first dielectric layer is considered to be an effectiveway to dissipate heat generated by the first transistor in the firstsemiconductor layer from the top of the transistor. In order to avoidthis from introducing any additional electrical induction or parasiticeffect to the transistor, the heat-dissipating component is preferablyimplemented as a heat sink made of a dielectric material with a highthermal conductivity. If the thermal conductivity is close to that ofsilicon, then heat dissipation capabilities that are substantially thesame as provided by the removed silicon substrate or close thereto canbe attained.

Further, in order to facilitate dissipation of heat through the top ofthe first transistor in the vertical direction, it is necessary toproperly select the thickness (usually smaller than 1 μm) and materialof the second dielectric layer.

Therefore, the dielectric material of the first heat sink sheet may beselected as, for example, boron nitride having a certain crystallinephase and a thermal conductivity of up to 200 W/m-K.

Similarly, in order for heat generated by the first transistor to beefficiently dissipated through its top, the RFIC device may furtherinclude a second heat sink sheet formed on the first dielectric. Thesecond heat sink sheet may be connected to the first heat sink sheet andis preferably located out of the vertical projection area of the firsttransistor. The second heat sink sheet may be formed of a metal with aneven higher thermal conductivity, including but not limited to aluminum,copper, titanium, cobalt, nickel, molybdenum, tin, lead, cadmium,silver, gold, platinum or an alloy thereof.

In another aspect, the present invention provides a method forfabricating the novel RFIC device as defined above. The method includes:

providing a first compound semiconductor substrate including a firstsemiconductor layer, a second dielectric layer on a second surface ofthe first semiconductor layer and a substrate layer on a surface of thesecond dielectric layer opposite to the first semiconductor layer;

fabricating a semiconductor component based on the first semiconductorlayer; forming a first dielectric layer covering the semiconductorcomponent; and

forming a sheet-like heat sink on a surface of the first dielectriclayer opposite to the first semiconductor layer for dissipating heatfrom the semiconductor component.

Compared with the prior art: according to the present invention,construction of efficient heat-dissipating components respectivelyexternal to the first and second dielectric layer is considered to be aneffective way to dissipate heat generated by the first transistor in thefirst semiconductor layer from the top of the transistor. In order toavoid this from introducing any additional electrical induction orparasitic effect to the transistor, the heat-dissipating components arepreferably implemented as heat sinks each made of a dielectric materialwith a high thermal conductivity. If the thermal conductivity is closeto that of silicon, then heat dissipation capabilities that aresubstantially the same as provided by the removed silicon substrate orclose thereto can be attained.

Additionally, in order to facilitate dissipation of heat from the firsttransistor, it is necessary to properly select the thickness (usuallysmaller than 1 μm) and material of the second dielectric layer.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1 to 4 schematically illustrate a method of fabricating an RFICdevice in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

As noted above, the present invention relates to a radio-frequencyintegrated circuit (RFIC) device such as an RF switch or another RFcomponent on a silicon-on-insulator (SOI) substrate and methods offabricating such a device, which will be described below with referenceto the accompanying drawings that are not necessarily drawn to scale.

Disclosed below are various embodiments in which various features of thepresent disclosure are implemented. For the sake of brevity of thepresent disclosure, particular embodiments of components andarrangements will be described below. It is a matter of course thatthese embodiments are presented merely by example and are not intendedto limit the present invention in any sense. For example, in thefollowing description, “under”, “below”, “underlying”, “overlying” andother spatial terms may be used to facilitate the explanation ofrelative locations between components shown in the figures. In additionto those shown in the figures, the spatial terms further include othervarious orientations of the device during its use or operation. Thedevice may be positioned in other orientations, for example, after itsrotation by 90 degrees, which will be explained with the spatial termsherein.

Silicon-on-insulator (SOI) substrates often utilize high-resistivityhandle substrates (HR-Si handle substrates). Such handle substratesimparts to SOI substrates the ability to meet the requirements ofspecific applications for, for example, a certain degree ofcomponent-to-component isolation or a certain Q-factor of a passivecomponent. In addition, they allow the shrinkage of CMOS components andhence hybrid integration and higher RF performance. All of these makeHR-Si handle substrates very attractive to mobile integrated systems.

SOI substrates have overwhelming advantages over bulk silicon. Itprovides IC components formed thereon with good dielectric isolationwhich immunizes them from parasitic latching that CMOS circuits formedon bulk silicon suffer from. In addition, ICs fabricated on SOIsubstrates offer the advantages including small parasitic capacitance, ahigh integration density, a high operating speed, simple fabricationprocesses, small short channel effects and high suitability for use aslow-voltage low-power consumption circuits. Thanks to their inherentadvantage of high insulation, CMOS devices on SOI substrates are idealfor use as key components and circuits at RF front-ends, including RFswitches, low SNR power amplifiers, modulators and their circuits.

The RFIC devices described in the following embodiments include RFswitches, low SNR power amplifiers, modulators, mobile integratedsystems and circuits thereof.

As used herein, the term “radio frequency (RF)” refers to a frequency ofelectromagnetic waves in the range of 3 Hz to 300 Hz for generation anddetection of radio waves. The RF spectrum covers the Very High Frequency(VFH), Ultra High Frequency (UHF), Super High Frequency (SHF) andExtremely High Frequency (EHF) bands. As used herein, the VHF band meansthe frequencies in the range of 30M Hz to 300M Hz, used for frequencymodulation (FM) broadcasting among its other applications; UHF bandmeans the frequencies in the range of 300 MHz to 3 GHz, used for mobilephones, wireless networks and microwave rates among its otherapplications; SHF band means the frequencies in the range of 3 GHz to 30GHz, used for wireless networks, radar and satellite links among itsother applications; and EHF means the frequencies in the range of 30 GHzto 300 GHz, corresponding to a millimeter wavelength of 1 mm to 10 mm,used for data links and remote sensing among its other applications.

Referring to FIG. 1, a first compound semiconductor substrate 100 isprovided. In a method for fabricating a radio-frequency integratedcircuit (RFIC) device in accordance with a first explanatory embodimentof the present invention, the first compound semiconductor substrate 100includes a first semiconductor layer 101, a second dielectric layer 102in connection with the first semiconductor layer 101, and a substratelayer 103 in connection with the second dielectric layer 102 and inopposition to the first semiconductor layer 101, i.e., not in connectionwith the first semiconductor layer 101. The first semiconductor layer101 has a first surface and a second surface parallel to the firstsurface. The second dielectric layer 102 is attached to the firstsemiconductor layer 101 via the second surface of the firstsemiconductor layer 101.

The first semiconductor layer 101 has a thickness smaller than 3 μm, andthe second dielectric layer 102 has a thickness smaller than 1 μm. Inparticular, when the RFIC device is used in an RF front-end, thethickness of the semiconductor layer may even be smaller than 0.2 μm.This, on one hand, is intended to reduce or even prevent, in thevertical direction, external electrical or electromagnetic interferenceby virtue of the two dielectric layers (i.e. the second dielectric layer102 and a first dielectric layer to be described later), and on theother hand, can minimize parasitic effects for transistors formed on thesemiconductor layer.

The first semiconductor layer 101 may be formed of a semiconductormaterial such as, for example, silicon, a silicon-containingsemiconductor, germanium, a silicon germanium alloy, a silicon-carbonalloy, gallium arsenide, indium arsenide, lead sulfide or another III-Vor II-VI compound semiconductor. The first semiconductor layer 101 isused for the formation of semiconductor components which may be 1 to N(N is a natural number) first transistors and other components of theRFIC device.

The second dielectric layer 102 is attached to the first semiconductorlayer 101 via the second surface of the first semiconductor layer 101.The second dielectric layer 102 may include at least one dielectricmaterial such as, for example, silicon dioxide, silicon nitride, siliconoxynitride, silicon oxide or any combination thereof and have athickness smaller than 1 μm, for example, 50-500 nm, typically 100-300nm.

The substrate layer 103 may be monocrystalline silicon, silicon oxide,silicon nitride or silicate glass and may be adapted to support thefirst compound semiconductor substrate 100.

Referring to FIG. 2, a first transistor 104 and a shallow trenchisolation (STI) 105 for isolating the first transistor 104 are formedbased on the first semiconductor layer 101. Doped regions in the firstsemiconductor layer 101 respectively serving as a source 104 s, a drain104 d and a conductive channel 104 c of the first transistor 104 areformed by different doping processes known to those skilled in the art,and description thereof in further detail is therefore deemedunnecessary. Above the channel 104 c is formed a gate 104 g. In additionto the first transistor 104, a second transistor, a third transistor andother RFIC devices may also be formed in the first semiconductor layer101.

The portion of the first semiconductor layer 101 surrounded and isolatedby the STI 105 is called a first semiconductor sheet, and the firsttransistor 104 is fabricated within the first semiconductor sheet andcovered by a first dielectric layer 106. Preferably, the firstsemiconductor sheet is formed of silicon or a silicon-containingsemiconductor.

The first dielectric layer 106 is formed over the first semiconductorlayer 101 by means of vapor deposition and includes at least onedielectric material such as silicon oxide, silicon nitride, siliconoxynitride or a combination thereof. It has a thickness of smaller than50 μm such as, for example, 10 μm. The first dielectric layer 106 isattached to the first semiconductor layer 101 via the first surface ofthe first semiconductor layer 101 so that the first dielectric layer 106covers the first transistor 104.

As shown in FIG. 3, a sheet-like heat sink 108 for dissipating heatgenerated by the semiconductor device is formed on the exposed surfaceof the first dielectric layer 106, i.e., the surface thereof opposite tothe first semiconductor layer 101. Preferably, the sheet-like heat sink108 includes a first heat sink sheet 108 a in a vertical projection areaof the first transistor 104, or a vertical projection area of the firstheat sink sheet 108 a on the first semiconductor layer 101 covers thefirst transistor 104. When there are more than one first transistor 104,each portion of the first heat sink sheet 108 a corresponds to arespective first transistor 104. In this embodiment, since thesheet-like heat sink 108 include only the first heat sink sheet 108 a,it itself is the first heat sink sheet 108 a, as shown in FIG. 3. Thesheet-like heat sink 108 may be a dielectric material with a thermalconductivity five times higher than that of the first dielectric layer106. As a result, with this efficient heat-dissipating component formedexternal to the first dielectric layer 106, heat generated by the firsttransistor 104 in the first semiconductor layer 101 can be dissipatedthrough its top. In order to avoid introducing any additional electricalinduction or parasitic effect to the transistor, the heat-dissipatingcomponent is preferably implemented as a heat sink made of a dielectricmaterial with a high thermal conductivity. If the thermal conductivityis close to that of silicon, then heat dissipation capabilities that aresubstantially the same as provided by the removed silicon substrate orclose thereto can be attained. For reference, silicon has a thermalconductivity of about 140 W/m-K at room temperature, and that of siliconoxide is approximately 0.2-1.4140 W/m-K (that of quartz glass is only0.7-11.7140 W/m-K). Aluminum nitride or another piezoelectric materialwith a high thermal conductivity (the thermal conductivity of aluminumnitride is comparable to that of silicon) may be suitably selected anddeposited and etched by conventional semiconductor thin-film processesso as to be compatible with CMOS processes.

The sheet-like heat sink 108 may be formed of a nitrogen-containingdielectric, an oxygen-containing dielectric, boron nitride, aluminum, analuminum-containing compound, copper, a copper-containing compound,aluminum nitride, diamond-like carbon or a combination thereof.

In one embodiment, the sheet-like heat sink 108 includes the first heatsink sheet 108 a in the vertical projection area of the first transistor104. The first heat sink sheet 108 a may be formed of a nitrogen- oroxygen-containing dielectric with a thermal conductivity of up to 30W/m-K. In this embodiment, the first heat sink sheet 108 a may beimplemented as a thermal conducting layer deposited by chemical vapordeposition (CVD) at a temperature in the range of 0° C. to 450° C., forexample, particularly at 200° C., 300° C. or 400° C. The first heat sinksheet 108 a may be formed in positional correspondence to the firsttransistor by etching the thermal conducting layer, for example, by adry or wet etching process, in which photolithographic alignment isperformed on its backside with respect to the side with features foroptical alignment taken as a front side.

In another embodiment, the first heat sink sheet 108 a is made ofaluminum nitride with a thermal conductivity of up to 140-180 W/m-K. Inthis embodiment, the first heat sink sheet may be fabricated bysputtering.

In another embodiment, the first heat sink sheet 108 a is made of, forexample, boron nitride having a certain crystalline phase and a thermalconductivity of up to 200 W/m-K.

In another embodiment, the first heat sink sheet 108 a is made ofdiamond-like carbon with a thermal conductivity of 1000 W/m-K.

Further, the sheet-like heat sink 108 may be formed of another metalthat is preferred depending on its thermal conductivity to be aluminum(thermal conductivity=237 W/m-K) or copper (thermal conductivity=401W/m-K).

The first heat sink sheet may also be formed of another structure in thesheet-like heat sink.

In another embodiment, the sheet-like heat sink 108 may further includeheat sink sheets corresponding to semiconductor components other thanthe first transistor so as to effectively dissipate heat from them.

Referring to FIG. 4, in another embodiment, in order to effectivelydissipate heat generated by the first transistor 104 through its top,the RFIC device further include a second heat sink sheet 109 on thesurface of the first dielectric layer 106 opposite to the firstsemiconductor layer 101 and in connection with the first heat sink sheet108 a. The second heat sink sheet 109 may be physically connected to thefirst heat sink sheet 108 a. As such, in this embodiment, the sheet-likeheat sink 108′ includes the first heat sink sheet 108 a and the secondheat sink sheet 109. The second heat sink sheet 109 is preferably formedof a metal with a higher thermal conductivity, including but not limitedto, aluminum, copper, titanium, cobalt, nickel, molybdenum, tin, lead,cadmium, silver, gold, platinum or an alloy thereof, out of the verticalprojection area of the first transistor 104.

The second heat sink sheet 109 may be formed by sputtering. Referring toFIG. 4, in another embodiment, the RFIC device further includes a thirddielectric layer 110 on the surface of the first dielectric layer 106opposite to the first semiconductor layer 101. The third dielectriclayer 110 may cover the sheet-like heat sink 108′ partially or entirely.

Referring to FIG. 4, in another embodiment, the RFIC device furtherincludes a third heat sink sheet 111 on the first dielectric layer 106(i.e., the surface thereof opposite to the first semiconductor layer101) and in physical connection with the second heat sink sheet 109. Thethird heat sink sheet 111 may be, for example, an alloy solder ball or awire.

The third heat sink sheet 111 may be formed by sputtering.

In another preferred embodiment, the substrate layer is thinned to aminor thickness but not entirely removed.

The present invention also provides a method for fabricating a radiofrequency integrated circuit (RFIC) device, the method including:

providing a first compound semiconductor substrate including a firstsemiconductor layer, a second dielectric layer attached to the firstsemiconductor layer via a second surface of the first semiconductorlayer and a substrate layer attached to the surface of the seconddielectric layer opposite to the first semiconductor layer;

fabricating a semiconductor component based on the first semiconductorlayer;

forming a first dielectric layer covering the semiconductor component;

providing a second substrate having a first surface on which asheet-like heat sink is formed; and

bonding the first surface of the second substrate to the firstdielectric layer of the first compound semiconductor substrate with thefirst dielectric layer as a bonding layer.

Preferably, the sheet-like heat sink includes a first heat sink sheetand a second heat sink sheet in connection with the first heat sinksheet.

Preferably, the second heat sink sheet is situated out of a verticalprojection area of the first transistor.

Accordingly, referring to FIG. 4, the present invention also provides anRFIC device fabricated by the method of the first embodiment of theinvention. The RFIC device includes the first semiconductor layer 101,the first dielectric layer 106, the second dielectric layer 102 and thesheet-like heat sink. The first semiconductor layer 101 has a firstsurface and a second surface parallel to the first surface. The firstdielectric layer 106 is attached to the first semiconductor layer 101via the first surface of the first semiconductor layer 101, and thesecond dielectric layer 102 is attached to the first semiconductor layer101 via the second surface of the first semiconductor layer 101. Each ofthe first dielectric layer 106 and the second dielectric layer 102includes at least one dielectric material. The first semiconductor layer101 includes 1 to N first transistors 104 and at least one shallowtrench isolation (STI) isolating the first transistors 104. Each firsttransistor 104 has the doped regions serving as its source 104 s, drain104 d and conductive channel 104 c formed in the first semiconductorlayer 101 and the gate 104 g formed in the first dielectric layer 106 incorrespondence with the channel 104 c. The first heat sink sheet 108 ais formed on the exposed surface of the first dielectric layer 106.

The first semiconductor layer 101 includes a semiconductor material suchas, for example, silicon, germanium, a silicon germanium alloy, asilicon-carbon alloy, gallium arsenide, indium arsenide, lead sulfide oranother III-V or II-VI compound semiconductor. The first semiconductorlayer 101 is used for the formation of semiconductor components whichmay be the first transistors 104 and other components necessary forconstruction of the RF device, for example, an RF switch.

In this embodiment, a first substrate is further formed on the surfaceof the second dielectric layer opposite to the first semiconductorlayer.

Each of the first dielectric layer 106 and the second dielectric layer102 includes at least one dielectric material such as, for example,silicon oxide, silicon nitride, silicon oxynitride or a combinationthereof and has a thickness between 50 nm and 500 nm, typically between100 nm and 300 nm.

In one embodiment, the first semiconductor layer 101 has a thickness ofsmaller than 3 μm, and the second dielectric layer has a thickness ofsmaller than 1 μM.

In one embodiment, the sheet-like heat sink is formed of a dielectricwith a thermal conductivity that is 5 times higher than that of thesecond dielectric layer.

In one embodiment, the sheet-like heat sink includes the first heat sinksheet 108 a located in the vertical projection area of the firsttransistor.

In one embodiment, the first semiconductor layer includes at least onefirst semiconductor sheet surrounded and isolated by the STI. The firsttransistor is formed within the first semiconductor sheet and the firstdielectric layer.

In one embodiment, the first semiconductor sheet is formed of silicon ora silicon-containing semiconductor.

In one embodiment, the second dielectric layer 102 is formed of anoxide, a nitride, silicon oxide, silicon nitride or a combinationthereof.

In one embodiment, the first heat sink sheet 108 a is formed of anitrogen-containing dielectric, an oxygen-containing dielectric, boronnitride, aluminum, an aluminum-containing compound, copper, acopper-containing compound or a combination thereof.

In one embodiment, the first heat sink sheet 108 a is formed of aluminumnitride and/or diamond-like carbon.

In one embodiment, the RFIC device further includes a third dielectriclayer 110 on the surface of the first dielectric layer 106 opposite tothe first semiconductor layer 101, the third dielectric layer 110covering the sheet-like heat sink partially or entirely.

In one embodiment, the sheet-like heat sink further includes a secondheat sink sheet 109 on the surface of the first dielectric layer 106opposite to the first semiconductor layer 101 and in connection with thefirst heat sink sheet 108 a.

In one embodiment, the second heat sink sheet 109 is located out of thevertical projection area of the first transistor 104.

In one embodiment, the second heat sink sheet 109 includes a metal thinfilm including aluminum, copper, titanium, cobalt, nickel, molybdenum,tin, lead, cadmium, silver, gold, platinum or an alloy thereof.

In one embodiment, the second heat sink sheet 109 is formed of anitrogen-containing dielectric, an oxygen-containing dielectric, boronnitride, aluminum, an aluminum-containing compound, copper, acopper-containing compound, diamond-like carbon or a combinationthereof.

In one embodiment, the sheet-like heat sink further includes a thirdheat sink sheet 111 on the surface of the first dielectric layer 106opposite to the first semiconductor layer 101 and in connection with thesecond heat sink sheet 109.

In one embodiment, the third heat sink sheet 111 is an alloy solder ballor a wire.

While the present invention has been described above with reference toseveral preferred embodiments, the invention is not limited there to inany sense. All changes or modifications made by those skilled in the artbased on the above disclosure of the present invention fall within thescope as defined by the appended claims.

What is claimed is:
 1. A radio frequency integrated circuit (RFIC)device, comprising: a first semiconductor layer having a first surface,a second surface and a thickness of smaller than 3 μm; a firstdielectric layer on the first surface of the first semiconductor layer;a semiconductor component within the first semiconductor layer and thefirst dielectric layer; a second dielectric layer on the second surfaceof the first semiconductor layer, the second dielectric layer having athickness of smaller than 1 μm; and a sheet-like heat sink formed on asurface of the first dielectric layer opposite to the firstsemiconductor layer for dissipating heat from the semiconductorcomponent; wherein the sheet-like heat sink is formed of a dielectricmaterial to avoid introducing any additional electrical induction orparasitic effect to the semiconductor component.
 2. The RFIC device ofclaim 1, further comprising a first substrate formed on a surface of thesecond dielectric layer opposite to the first semiconductor layer. 3.The RFIC device of claim 1, wherein the semiconductor componentcomprises at least one transistor.
 4. The RFIC device of claim 1,wherein the dielectric material has a thermal conductivity five timeshigher than a thermal conductivity of the first dielectric layer.
 5. TheRFIC device of claim 3, wherein the sheet-like heat sink comprises afirst heat sink sheet arranged in a vertical projection area of the atleast one transistor.
 6. The RFIC device of claim 5, wherein the firstheat sink sheet is formed of a nitrogen-containing dielectric, anoxygen-containing dielectric, boron nitride, aluminum, analuminum-containing compound, copper, a copper-containing compound or acombination thereof.
 7. The RFIC device of claim 5, wherein the firstheat sink sheet is formed of aluminum nitride and/or diamond-likecarbon.
 8. The RFIC device of claim 1, further comprising a thirddielectric layer formed on the surface of the first dielectric layeropposite to the first semiconductor layer, the third dielectric layercovering the sheet-like heat sink partially or entirely.
 9. The RFICdevice of claim 5, wherein the sheet-like heat sink further comprises asecond heat sink sheet arranged out of the vertical projection area ofthe at least one transistor and in connection with the first heat sinksheet.
 10. The RFIC device of claim 9, wherein the second heat sinksheet is formed of a metal thin film including aluminum, copper,titanium, cobalt, nickel, molybdenum, tin, lead, cadmium, silver, gold,platinum or an alloy thereof.
 11. The RFIC device of claim 9, whereinthe second heat sink sheet is formed of a nitrogen-containingdielectric, an oxygen-containing dielectric, boron nitride, aluminum, analuminum-containing compound, copper, a copper-containing compound,diamond-like carbon or a combination thereof.
 12. The RFIC device ofclaim 9, wherein the sheet-like heat sink further comprises a third heatsink sheet in connection with the second heat sink sheet, the third heatsink sheet implemented as an alloy solder ball or a wire.
 13. A methodof fabricating the radio frequency integrated circuit (RFIC) device asdefined in claim 1, comprising: providing a first compound semiconductorsubstrate comprising a first semiconductor layer, a second dielectriclayer on a second surface of the first semiconductor layer and asubstrate layer on a surface of the second dielectric layer opposite tothe first semiconductor layer; fabricating a semiconductor componentbased on the first semiconductor layer; forming a first dielectric layercovering the semiconductor component; and forming a sheet-like heat sinkon a surface of the first dielectric layer opposite to the firstsemiconductor layer for dissipating heat from the semiconductorcomponent.
 14. The method of claim 13, wherein the semiconductorcomponent comprises at least one transistor, and wherein the sheet-likeheat sink comprises a first heat sink sheet arranged in a verticalprojection area of the at least one transistor.
 15. The method of claim13, further comprising, subsequent to the formation of the sheet-likeheat sink: forming, on the surface of the first dielectric layeropposite to the first semiconductor layer, a third dielectric layercovering the sheet-like heat sink partially or entirely.
 16. The methodof claim 14, further comprising, subsequent to the formation of thefirst heat sink sheet vertically corresponding to the at least onetransistor: forming, on the surface of the first dielectric layeropposite to the first semiconductor layer, a second heat sink sheetconnected to the first heat sink sheet and arranged out of the verticalprojection area of the at least one transistor.
 17. The method of claim16, further comprising, subsequent to the formation of the second heatsink sheet in connection with the first heat sink sheet: forming, on thesurface of the first dielectric layer opposite to the firstsemiconductor layer, a third heat sink sheet in connection with thesecond heat sink sheet.
 18. A method of fabricating the radio frequencyintegrated circuit (RFIC) device as defined in claim 1, comprising:providing a first compound semiconductor substrate comprising a firstsemiconductor layer, a second dielectric layer on a second surface ofthe first semiconductor layer and a substrate layer on a surface of thesecond dielectric layer opposite to the first semiconductor layer;fabricating a semiconductor component based on the first semiconductorlayer; forming a first dielectric layer covering the semiconductorcomponent; providing a second substrate having a first surface with asheet-like heat sink formed thereon; and bonding the first surface ofthe second substrate to the first dielectric layer of the first compoundsemiconductor substrate with the first dielectric layer serving as abonding layer.
 19. The method of claim 18, wherein the semiconductorcomponent comprises at least one transistor.
 20. The method of claim 19,wherein the sheet-like heat sink comprises a first heat sink sheetarranged in a vertical projection area of the at least one transistorand a second heat sink sheet arranged out of the vertical projectionarea of the at least one transistor and in connection with the firstheat sink sheet.